Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   2                    Egg yolks
     3/4  cup           Sugar
   3      tablespoons   Butter
   1      teaspoon      Lemon rind -- grated
   2      tablespoons   Lemon juice
   1 1/2  tablespoons   Cornstarch
   3      tablespoons   Water

Preparation:

Combine egg yolks, sugar, butter rind, and lemon juice in top half of a double boiler. Cook over simmering water until quite thick, then cool slightly. Mix cornstarch with water and stir into lemon mixture. Cool before spreading on cheese cakes.